path: root/debian/patches/0004-Add-a-minimalist-init-program.patch

From 78672310f29185d1a9605dfc1b2fc4f4c8d6def3 Mon Sep 17 00:00:00 2001
From: Justus Winter <4winter@informatik.uni-hamburg.de>
Date: Wed, 18 Sep 2013 15:29:36 +0200
Subject: [PATCH 4/8] Add a minimalist init program

---
 Makefile               |   1 +
 daemons/runsystem.hurd | 142 ++++++++++++++++++++++++++++++++++++++++++++
 daemons/runsystem.sh   |  90 ++++++++++------------------
 init/Makefile          |  24 ++++++++
 init/init.c            | 155 +++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 352 insertions(+), 60 deletions(-)
 create mode 100644 daemons/runsystem.hurd
 create mode 100644 init/Makefile
 create mode 100644 init/init.c

diff --git a/Makefile b/Makefile
index 455df67..3178740 100644
--- a/Makefile
+++ b/Makefile
@@ -41,6 +41,7 @@ prog-subdirs = auth proc exec term \
 	       random \
 	       procfs \
 	       startup \
+	       init \
 
 ifeq ($(HAVE_SUN_RPC),yes)
 prog-subdirs += nfs nfsd
diff --git a/daemons/runsystem.hurd b/daemons/runsystem.hurd
new file mode 100644
index 0000000..c3cb2d6
--- /dev/null
+++ b/daemons/runsystem.hurd
@@ -0,0 +1,142 @@
+#!/bin/bash
+#
+# This program is run by /hurd/init at boot time after the essential
+# servers are up, and is responsible for running the "userland" parts of a
+# normal system.  This includes running the single-user shell as well as a
+# multi-user system.  This program is expected never to exit.
+#
+
+
+###
+### Where to find programs, etc.
+###
+
+PATH=/bin:/sbin
+export PATH
+
+umask 022
+
+# If we lose badly, try to exec each of these in turn.
+fallback_shells='/bin/sh /bin/bash /bin/csh /bin/ash /bin/shd'
+
+# Shell used for normal single-user startup.
+SHELL=/bin/sh
+
+# Programs that do multi-user startup.
+RUNCOM=/libexec/rc
+RUNTTYS=/libexec/runttys
+# Signals that we should pass down to runttys.
+runttys_sigs='TERM INT HUP TSTP'
+
+###
+
+
+# If we get a SIGLOST, attempt to reopen the console in case
+# our console ports were revoked.  This lets us print messages.
+function reopen_console ()
+{
+  exec 1>/dev/console 2>&1 || exit 3
+}
+trap 'reopen_console' SIGLOST
+
+
+# Call this when we are losing badly enough that we want to punt normal
+# startup entirely.  We exec a single-user shell, so we will not come back
+# here.  The only way to get to multi-user from that shell will be
+# explicitly exec this script or something like that.
+function singleuser ()
+{
+  test $# -eq 0 || echo "$0: $*"
+  for try in ${fallback_shells}; do
+    SHELL=${try}
+    exec ${SHELL}
+  done
+  exit 127
+}
+
+
+# We expect to be started by console-run, which gives us no arguments and
+# puts FALLBACK_CONSOLE=file-name in the environment if our console is
+# other than a normal /dev/console.
+
+if [ "${FALLBACK_CONSOLE+set}" = set ]; then
+  singleuser "Running on fallback console ${FALLBACK_CONSOLE}"
+fi
+
+
+###
+### Normal startup procedures
+###
+
+# Parse the multiboot command line.  We only pay attention to -s and -f.
+# The first argument is the kernel file name; skip that.
+shift
+flags=
+while [ $# -gt 0 ]; do
+  arg="$1"
+  shift
+  case "$arg" in
+  --*) ;;
+  *=*) ;;
+  -*)
+    flags="${flags}${arg#-}"
+    ;;
+  'single'|'emergency') # Linux compat
+    flags="${flags}s"
+    ;;
+  'fastboot')
+    flags="${flags}f"
+    ;;
+  esac
+done
+
+# Check boot flags.
+case "$flags" in
+*s*)
+  rc=false			# force single-user
+  ;;
+*f*)
+  rc="${RUNCOM}"		# fastboot
+  ;;
+*)
+  rc="${RUNCOM} autoboot"	# multi-user default
+  ;;
+esac
+
+# Large infinite loop.  If this script ever exits, init considers that
+# a serious bogosity and punts to a fallback single-user shell.
+# We handle here the normal transitions between single-user and multi-user.
+while : ; do
+
+  # Run the rc script.  As long as it exits nonzero, punt to single-user.
+  # After the single-user shell exits, we will start over attempting to
+  # run rc; but later invocations strip the `autoboot' argument.
+  until $rc; do
+    rc=${RUNCOM}
+
+    # Run single-user shell and repeat as long as it dies with a signal.
+    until ${SHELL} || test $? -lt 128; do
+      :
+    done
+  done
+
+  # Now we are officially ready for normal multi-user operation.
+
+  # Trap certain signals and send them on to runttys.  For this to work, we
+  # must run it asynchronously and wait for it with the `wait' built-in.
+  runttys_pid=0
+  for sig in $runttys_sigs; do
+    trap "kill -$sig \${runttys_pid}" $sig
+  done
+
+  # This program reads /etc/ttys and starts the programs it says to.
+  ${RUNTTYS} &
+  runttys_pid=$!
+
+  # Wait for runttys to die, meanwhile handling trapped signals.
+  wait
+
+  # Go back to the top of the infinite loop, as if booting single-user.
+  rc=false
+
+done
diff --git a/daemons/runsystem.sh b/daemons/runsystem.sh
index f4f2771..39447ca 100644
--- a/daemons/runsystem.sh
+++ b/daemons/runsystem.sh
@@ -1,9 +1,9 @@
 #!/bin/bash
 #
 # This program is run by /hurd/init at boot time after the essential
-# servers are up, and is responsible for running the "userland" parts of a
-# normal system.  This includes running the single-user shell as well as a
-# multi-user system.  This program is expected never to exit.
+# servers are up.  It does some initialization of its own and then
+# execs the SysV init to bring up the "userland" parts of a normal
+# system.
 #
 
 
@@ -22,29 +22,27 @@ fallback_shells='/bin/sh /bin/bash /bin/csh /bin/ash /bin/shd'
 # Shell used for normal single-user startup.
 SHELL=/bin/sh
 
-# Programs that do multi-user startup.
-RUNCOM=/libexec/rc
-RUNTTYS=/libexec/runttys
-# Signals that we should pass down to runttys.
-runttys_sigs='TERM INT HUP TSTP'
+# The init program to call.
+#
+# Can be overridden using init=something in the kernel command line.
+init=/sbin/init
 
 ###
 
-
 # If we get a SIGLOST, attempt to reopen the console in case
 # our console ports were revoked.  This lets us print messages.
-function reopen_console ()
+reopen_console ()
 {
   exec 1>/dev/console 2>&1 || exit 3
 }
-trap 'reopen_console' SIGLOST
+trap 'reopen_console' 32 # SIGLOST = server died on GNU
 
 
 # Call this when we are losing badly enough that we want to punt normal
 # startup entirely.  We exec a single-user shell, so we will not come back
 # here.  The only way to get to multi-user from that shell will be
 # explicitly exec this script or something like that.
-function singleuser ()
+singleuser()
 {
   test $# -eq 0 || echo "$0: $*"
   for try in ${fallback_shells}; do
@@ -54,12 +52,14 @@ function singleuser ()
   exit 127
 }
 
+# Print a newline.
+echo
 
-# See whether pflocal is set up already, and do so if not (install case)
+# See whether pflocal is setup
 #
 # Normally this should be the case, but we better make sure since
 # without the pflocal server, pipe(2) does not work.
-if ! test -e /servers/socket/1 ; then
+if ! test -e /servers/socket/1 && which settrans >/dev/null ; then
   # The root filesystem should be read-only at this point.
   if fsysopts / --update --writable ; then
     settrans -c /servers/socket/1 /hurd/pflocal
@@ -76,7 +76,6 @@ if [ "${FALLBACK_CONSOLE+set}" = set ]; then
   singleuser "Running on fallback console ${FALLBACK_CONSOLE}"
 fi
 
-
 ###
 ### Normal startup procedures
 ###
@@ -85,20 +84,23 @@ fi
 # The first argument is the kernel file name; skip that.
 shift
 flags=
+single=
 while [ $# -gt 0 ]; do
   arg="$1"
   shift
   case "$arg" in
   --*) ;;
+  init=*)
+    eval "${arg}"
+    ;;
   *=*) ;;
   -*)
     flags="${flags}${arg#-}"
     ;;
-  'single'|'emergency') # Linux compat
-    flags="${flags}s"
+  'single')
+    single="-s"
     ;;
-  'fastboot')
-    flags="${flags}f"
+  'fastboot'|'emergency')
     ;;
   esac
 done
@@ -106,50 +108,18 @@ done
 # Check boot flags.
 case "$flags" in
 *s*)
-  rc=false			# force single-user
-  ;;
-*f*)
-  rc="${RUNCOM}"		# fastboot
-  ;;
-*)
-  rc="${RUNCOM} autoboot"	# multi-user default
+  single="-s"			# force single-user
   ;;
 esac
 
-# Large infinite loop.  If this script ever exits, init considers that
-# a serious bogosity and punts to a fallback single-user shell.
-# We handle here the normal transitions between single-user and multi-user.
-while : ; do
-
-  # Run the rc script.  As long as it exits nonzero, punt to single-user.
-  # After the single-user shell exits, we will start over attempting to
-  # run rc; but later invocations strip the `autoboot' argument.
-  until $rc; do
-    rc=${RUNCOM}
-
-    # Run single-user shell and repeat as long as it dies with a signal.
-    until ${SHELL} || test $? -lt 128; do
-      :
-    done
-  done
-
-  # Now we are officially ready for normal multi-user operation.
-
-  # Trap certain signals and send them on to runttys.  For this to work, we
-  # must run it asynchronously and wait for it with the `wait' built-in.
-  runttys_pid=0
-  for sig in $runttys_sigs; do
-    trap "kill -$sig \${runttys_pid}" $sig
-  done
-
-  # This program reads /etc/ttys and starts the programs it says to.
-  ${RUNTTYS} &
-  runttys_pid=$!
+# Start the default pager.  It will bail if there is already one running.
+/hurd/mach-defpager
 
-  # Wait for runttys to die, meanwhile handling trapped signals.
-  wait
+# This is necessary to make stat / return the correct device ids.
+# Work around a race condition (probably in the root translator).
+for i in `seq 1 100000` ; do : ; done
 
-  # Go back to the top of the infinite loop, as if booting single-user.
-  rc=false
+fsysopts / --update --readonly
 
-done
+# Finally, start the actual SysV init.
+exec ${init} ${single} -a
diff --git a/init/Makefile b/init/Makefile
new file mode 100644
index 0000000..07b8026
--- /dev/null
+++ b/init/Makefile
@@ -0,0 +1,24 @@
+#
+#   Copyright (C) 2013 Free Software Foundation, Inc.
+#
+#   This program is free software; you can redistribute it and/or
+#   modify it under the terms of the GNU General Public License as
+#   published by the Free Software Foundation; either version 2, or (at
+#   your option) any later version.
+#
+#   This program is distributed in the hope that it will be useful, but
+#   WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+#   General Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License
+#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+dir := init
+makemode := server
+
+SRCS = init.c
+OBJS = $(SRCS:.c=.o)
+target = init
+
+include ../Makeconf
diff --git a/init/init.c b/init/init.c
new file mode 100644
index 0000000..b3d3301
--- /dev/null
+++ b/init/init.c
@@ -0,0 +1,155 @@
+/* A minimalist init for the Hurd
+
+   Copyright (C) 2013,14 Free Software Foundation, Inc.
+   This file is part of the GNU Hurd.
+
+   The GNU Hurd is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   The GNU Hurd is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with the Hurd.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include <argp.h>
+#include <error.h>
+#include <hurd.h>
+#include <signal.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <version.h>
+
+const char *argp_program_version = STANDARD_HURD_VERSION (init);
+static pid_t child_pid;
+static int single;
+
+static struct argp_option
+options[] =
+{
+  /* XXX: Currently, -s does nothing.  */
+  {"single-user", 's', NULL, 0, "Startup system in single-user mode", 0},
+  {NULL, 'a', NULL, 0, "Ignored for compatibility with sysvinit", 0},
+  {0}
+};
+
+static char doc[] = "A minimalist init for the Hurd";
+
+static error_t
+parse_opt (int key, char *arg, struct argp_state *state)
+{
+  switch (key)
+    {
+    case 's':
+      single = 1;
+      break;
+
+    case 'a':
+      /* Ignored.  */
+      break;
+
+    default:
+      return ARGP_ERR_UNKNOWN;
+    }
+
+  return 0;
+}
+
+void
+sigchld_handler(int signal)
+{
+  /* A child died.  Find its status.  */
+  int status;
+  pid_t pid;
+
+  while (1)
+    {
+      pid = waitpid (WAIT_ANY, &status, WNOHANG | WUNTRACED);
+      if (pid <= 0)
+	break;		/* No more children.  */
+
+      /* Since we are init, orphaned processes get reparented to us and
+	 alas, all our adopted children eventually die.  Woe is us.  We
+	 just need to reap the zombies to relieve the proc server of
+	 its burden, and then we can forget about the little varmints.  */
+
+      if (pid == child_pid)
+	{
+	  /* The big magilla bit the dust.  */
+	  child_pid = -1;
+
+	  char *desc = NULL;
+	  if (WIFSIGNALED (status))
+	    asprintf (&desc, "terminated abnormally (%s)",
+		      strsignal (WTERMSIG (status)));
+	  else if (WIFSTOPPED (status))
+	    asprintf (&desc, "stopped abnormally (%s)",
+		      strsignal (WTERMSIG (status)));
+	  else if (WEXITSTATUS (status) == 0)
+	    desc = strdup ("finished");
+	  else
+	    asprintf (&desc, "exited with status %d",
+		      WEXITSTATUS (status));
+
+	  error (0, 0, "child %s", desc);
+	  free (desc);
+
+	  /* XXX: launch emergency shell.  */
+	  error (23, 0, "panic!!");
+	}
+    }
+}
+
+int
+main (int argc, char **argv)
+{
+  struct argp argp =
+    {
+      .options = options,
+      .parser = parse_opt,
+      .doc = doc,
+    };
+  argp_parse (&argp, argc, argv, 0, 0, 0);
+
+  if (getpid () != 1)
+    error (1, 0, "can only be run as PID 1");
+
+  struct sigaction sa;
+  sa.sa_handler = SIG_IGN;
+  sa.sa_flags = 0;
+  sigemptyset (&sa.sa_mask);
+
+  sigaction (SIGHUP, &sa, NULL);
+  sigaction (SIGINT, &sa, NULL);
+  sigaction (SIGQUIT, &sa, NULL);
+  sigaction (SIGTERM, &sa, NULL);
+  sigaction (SIGUSR1, &sa, NULL);
+  sigaction (SIGUSR2, &sa, NULL);
+  sigaction (SIGTSTP, &sa, NULL);
+
+  sa.sa_handler = sigchld_handler;
+  sa.sa_flags |= SA_RESTART;
+  sigaction (SIGCHLD, &sa, NULL);
+
+  char *args[] = { "/etc/hurd/runsystem.hurd", NULL };
+
+  switch (child_pid = fork ())
+    {
+    case -1:
+      error (1, errno, "failed to fork");
+    case 0:
+      execv (args[0], args);
+      error (2, errno, "failed to execv child");
+    }
+
+  select (0, NULL, NULL, NULL, NULL);
+  /* Not reached.  */
+  return 0;
+}
-- 
2.1.0